Eembeandt lockwood



UNITED- El W11nnr'r rrren REM'BRAND'T Loo-K'Woon, OF'BROOKLYN, NEW YORK.

IMPROVEMENTI'IIN P'RocEssE'so'F TREATING wooo.

Specification forming part of Letters Patent No. 74,914; dated March 21', 1876; application filed October 2, 1875.

To all whom it may concern:

Be it known that I, REMBRANDT LocKWooD, of the city of Brooklyn, Kings county, State of New York, have invented a new and useful Improvement in Oompfessed Wood, of which the following is a full and clear specification:

The object of my invention is to form a close, hard, compact, and almost homogeneous material, by taking almost any of the native or foreign woods, and by a process, hereinafter mentioned, make it hard and closegrained, so as to adapt it to the purposes required in many of the arts, as, for instance, a substitute for box-wood for engraving on, or for making the larger kinds of type-letters to print from, or any other use that hard, close, and-tough grained wood would be desirable.

As box-wood is every year growing more scarce, and even now dit'ticult to obtain in large quantities or sizes, this article (compressed wood) would make a substitute for box-wood at a much reduced price, and "at the same time fill a want much felt in the art of wood-engraving.

All wood is composed of tissues or woody fiber. Tissues of wood consist of collections of cellular pores of general uniform character, permanently combined together by the more or less complete union of their outer surfaces. In these cellular pores circulate, in the plantlife, the sap that goes to make the fiber ot' the wood.

The nature of my invention consists in takin g advantage of the above constitution of the cellular pores of wood by preparing it in the following manner: I first cut the wood in small lengths transversely across the fiber of the wood, from two to six inches, more or less, in length, then boiling the wood in water, or steaming it, until all the matter contained in the pores of the wood not yet formed into woody fiber shall be softened. In boiling or steaming I sometimes add a small quantity of potash or soda to the water to assist in removing any resinous or pitchy matter that may be in the wood. I then remove the wood while yet warm to a press of considerable power, say, three tons, more or less, laying the grain of the wood in horizontal position, put it under sufficient pressure to exclude the soft matter from the cellular pores of the wood- I then remove the wood and allow it to dry thoroughly, either in the open air or in a drying-room by heat, it I wish to quicken the process. In this state the wood has a somewhat spongy appearance; which will be readily seen by subjecting a piece to pressure, by its being easily compressed, showing that the pores of the wood are open, and that, by pressure, are

I made to yield, the sides of the open pores to collapse or come together. The wood is now ready for the next stage of the process, which is that of immersing and boiling in glue, or its equivalent, which should be of the best quality of light-colored glue, for good work, care being taken that it is not too thick. The glue will be taken up by capillary attraction, or, if preferred, maybe forced in by pressure, but by my experience I have found that capillary attraction answers every purpose. The wood is now, while hot, removed to the press, laid with the grain or fiber of the wood in a horizontal position, so as to press the sides of the fiber or pores of the wood, and by pressure to expel all surplus glue, and to press the sides of the cellular fiber, so that they shall come together and be glued, making a solid mass of great density. In this state the wood is allowed to dry under pressure. When dry, remove the wood from the press, and dress the outside surface. The wood is now ready to be put in shape for any purpose or use that hard, tough, and compact wood may be called for.

It will be seen by the foregoing description of the process of making compressed wood, it is not filling the pores with any material, but on the contrary, freeing them of all their natural and other contents, and then gluing their sides together by collapsing the pores under pressure, so as to form a solid mass of fiber. We have only to consider the strength of wood when two or more pieces are glued together in a proper manner, with good glue, to realize the immense density of wood when any individual pore of the wood is glued together under pressure in one solid mass. If desired, the wood can be tinted in the boiling process, almost any desired color, from black, to represent ebony, to canary-yellow, to represent box-wood. When some of thelightercolored woods are used, such as white pine, the result is an admirable substitute for boxwood for engraving purposes.

It is not absolutely essential to dry the wood, after the pores shall have been emptied, before the glue is introduced, as under some conditions the wood may be taken directly from its first pressure and immersed in the glue.

I do not claim as new the boiling or steam-.

ing of wood to fit it for other operations, as this is a common and well-known process. Neither do I claim to fill the pores with resinous or other equivalent substances, as I desire to get rid of all such fillings, but

Having described my invention, I claim- The process of treating wood for various 

